PVC dinghy rebuild

[RichB]

My West Marine 310 type PVC inflatable w/ fiberglass bottom came apart at the hull to tube joint... (the whole darn thing except the transom)
Both strips holding the bottom to the tubes, (inside and out) failed at the PVC to PVC tube glue-joint, while the adjacent glue-joint to the fiberglass seems secure.

I don't know the exact age, as she came with the boat 3 years ago. The tube holds air and seems to be sound.
I want to do it right, so I see 2 issues beyond getting the glue to stick.

First, Are there any tried and true procedural tricks to insure success? LIKE.. Should I buy new PVC strips for longer lifespan? and should I start by un-gluing the bottom so as to get a good bond between PVC strip and PVC tube... ie: what is the best order of operations?

Second issue is , assuming that all the 2-part glue choices, ranging from Cliftons to Poly-Marine to G-Flex will work. Is there a favorite glue choice? Is there a preferred supplier?

I will be cleaning off old glue waiting for a clear path to take. Thank you.

[bensolomon]

I had a similar issue, but my dinghy is hypalon. I used MEK (methyl ethyl ketone) and cleaned off all the old glue. My transom had also separated. I used polymarine two part glue. I followed the directions and it worked great! I know they have similar PVC glue.

Good luck! It is very satisfying when finished!

[KD8NPB]

Climate control is mandatory.

Two part adhesive cannot be used above ~75F and above 65% humidity. The isocyanate reacts with the water and breaks down almost instantly. The heat causes the cure to over-accelerate. In addition to it, the solvents used are hygroscopic in some cases, so the adhesive will absorb moisture from the air if the humidity is too high.

If you ignore my cautionary tale, your repairs will last about 1 to 3 months before it starts peeling off again.

Prep is also mandatory. PVC plasticizers are not compatible with the adhesive, and must be removed with degreaser / scrubbing, then solvent before adhesive application.

[Boatguy30]

West System Gflex works best. Sand the mating surfaces with some 40 grit and clean with MEK or acetone. Or hot TSP and water

[KD8NPB]

Originally Posted by Boatguy30

West System Gflex works best. Sand the mating surfaces with some 40 grit and clean with MEK or acetone. Or hot TSP and water

I strongly recommend against GFlex on PVC or CSM/CR. It works okay for TPR and EPDM, but not for flexible material.

[RichB]

Thanks folks. the insight is much appreciated. Florida is experiencing (close to 2 weeks now) rainy airflow from the South. Summer is close and nightly temps will bottom out in the high 70s while humidity hits 100% at sunrise and hovers in the 60% range daily. Oh well, it is simply the price we pay for living in the lightning capital..!... All that to observe that I have probably missed the weather window this year for outdoor application of 2-part glue.

Having read the Poly-Marine instructions/brochure, I continue to wonder if any of the other 4 or 5 brands are preferred for ease of handling or longevity (or any other reason). Also if there is a preferred supplier.

Second: With the cautionary tale firmly heartened, and considering it is a double sided glue-job with the top/interior strip folded back on itself and hidden between hull and tube, it seems logical to place the inside strip on the tube first. Then affix that strip to the top/inside of the fiberglass hull. Finally flipping the boat over to install the outside strip. Any more comment will be appreciated.

[KeelMe]

NRS builds both PVC and Hypalon boats and offer for sale the glues they use. NRS has higher than average prices but most of these glues have a short shelf life and expiration dates; they sell enough to have a good stock of current adhesive.

I highly recommend watching their videos on Inflatable boat repair.

[Boatguy30]

I should say, I've had great success with Gflex on PVC and hypalon ribs. Boats that are never really deflated so full flexibility not needed. Does need to be clamped some way which is a disadvantage.

I'm thinking of gluing a set of Avon tubes I have onto a zodiac rib hull I found in the trash after the tubes fell off.

[bensolomon]

Originally Posted by RichB

Thanks folks. the insight is much appreciated. Florida is experiencing (close to 2 weeks now) rainy airflow from the South. Summer is close and nightly temps will bottom out in the high 70s while humidity hits 100% at sunrise and hovers in the 60% range daily. Oh well, it is simply the price we pay for living in the lightning capital..!... All that to observe that I have probably missed the weather window this year for outdoor application of 2-part glue.

Having read the Poly-Marine instructions/brochure, I continue to wonder if any of the other 4 or 5 brands are preferred for ease of handling or longevity (or any other reason). Also if there is a preferred supplier.

Second: With the cautionary tale firmly heartened, and considering it is a double sided glue-job with the top/interior strip folded back on itself and hidden between hull and tube, it seems logical to place the inside strip on the tube first. Then affix that strip to the top/inside of the fiberglass hull. Finally flipping the boat over to install the outside strip. Any more comment will be appreciated.

You will also have to strap the tubes together to secure the transom.

[wingssail]

Originally Posted by KD8NPB

Climate control is mandatory.

Two part adhesive cannot be used above ~75F and above 65% humidity. The isocyanate reacts with the water and breaks down almost instantly. The heat causes the cure to over-accelerate. In addition to it, the solvents used are hygroscopic in some cases, so the adhesive will absorb moisture from the air if the humidity is too high.

If you ignore my cautionary tale, your repairs will last about 1 to 3 months before it starts peeling off again.

Prep is also mandatory. PVC plasticizers are not compatible with the adhesive, and must be removed with degreaser / scrubbing, then solvent before adhesive application.

That must make it pretty hard to fix a dingy in the tropics, say, Papua New Guinea.